An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be Option A: 100 W Option B: 75 W Option C: 50 W Option D: 25 W

Correct option: D
R=V2/P
= (220)2/100
= 484Ohm
The resistance of the bulb remains constant
if the supply voltage is reduced to 110 V then Vʹ=110 V
the power consumed by it is given by the expression = Vʹ2/R = (110)2/484= 25w

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